Ken Mattingly, astronaut. NASA.
He was the command module pilot for Apollo 16 and commanded two shuttle missions (STS-4 and STS-51C). But he’s perhaps most famous for a mission he didn’t fly.
He was scheduled to be the command module pilot for Apollo 13, but was pulled from the mission at the last minute (after it was determined he’d been exposed to measles) and was replaced by Jack Swigert. We all know what happened next.
Commander Mattingly did not, in fact, develop German measles, and he played a significant part in the plan developed by the astronauts and mission control in Houston to get them home safely.
The three astronauts crowded into the undamaged lunar module, although it had been built to hold only two astronauts and was designed solely for landing on the moon and then returning to the orbiting mother ship.
Commander Mattingly read off a long and detailed list of instructions for the astronauts to follow as they used the lunar lander as a “lifeboat” to get them back toward Earth while short on power and food.
Interview with Mr. Mattingly: